Pack of 10 Organ Brand Flat Shank Serger Overlock Needles. Needle system* : SLX75 SLX75 Needles are also sold under needle system 2054, SY2054 and 16X75. *A needle system is a group of needles made to fit specific sewing machines. All needles in a system are of the same length and shank size, but are of various diameters. Lower size numbers are narrower or thinner needles used for lighter materials. Higher size numbers indicate a needle of thicker diameter, used for heavier materials. Match your needle system to your machine, then the size of the needle to the product you are sewing. Organ SLX75 needles are available in following sizes. Please select your size. Singer Size 11 (Metric Size 75) Singer Size 12 (Metric Size 80) Singer Size 14 (Metric Size 90) Singer Size 16 (Metric Size 100) These are thin flat shank needles fit most Singer 14U series sergers including : 14U32, 14U34, 14U234, 14U44, 14U46, 14U286, 14U285, 14U344, 14U 354, 14U444, 14U454, 14U85, 14U65 and more Also fit Pfaff 756 Serger.